External Beam Radiation Therapy

In external beam radiation therapy, radiation is produced by a machine called a linear accelerator. Short bursts of x-rays are directed from the machine at your cancer. The x-rays come out in a square-shaped manner. The radiation oncologist designs special blocks to shape the radiation beam so that it treats the cancer and as little normal tissue as possible.
Before treatment actually begins, your doctor will design specific treatment fields and prepare either computer programs or blocks to shape the treatment beam to fit your particular situation.

Like
chemotherapy
, the side effects from radiation result from injury to the normal tissues. There are many new ways that your treatment can be customized to try to kill as much cancer while sparing as much normal tissue as possible. The radiation oncologist will determine how many treatments you will receive. Sometimes they will be once a day and sometimes twice a day. Each treatment generally only takes a few minutes. The total treatment time can range from 5-8 weeks depending on the total dose required.

Radiation therapy can be given to treat cancer at its initial site or after it has spread. In some cases, after cancer has spread, radiation is no longer curative. However, the treatments can help resolve problems that the cancer may be causing, including local pain and weakness.

Many people believe that when you have received a certain dose of radiation you can no longer get any more treatment. It is true that each tissue in the body can only safely tolerate a certain dose of radiation. However, the therapy is very focused. It is possible that you can get additional treatments to an already treated area or certainly to an area not yet treated. Ask your radiation oncologist about what dose you can safely receive.

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.